https://scholars.lib.ntu.edu.tw/handle/123456789/410393
標題: | Yellowish and blue luminescent graphene oxide quantum dots prepared: Via a microwave-assisted hydrothermal route using H 2 O 2 and KMnO 4 as oxidizing agents | 作者: | Hu C. Su T.-R. Lin T.-J. Chang C.-W. Tung K.-L. |
公開日期: | 2018 | 卷: | 42 | 期: | 6 | 起(迄)頁: | 3999-4007 | 來源出版物: | New Journal of Chemistry | 摘要: | Graphene oxide quantum dots (GOQDs) with different oxygenation levels were successfully prepared using a facile, rapid, and cost-effective microwave-assisted hydrothermal method under neutral conditions using hydrogen peroxide (MGOH) or potassium permanganate (MGOK) as an oxidizing agent. GOQDs with an average diameter of 7-12 nm for both MGOH and MGOK samples were observed using transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses revealed that MGOH exhibited a high quantity of C-O and CO groups in its structure, whereas MGOK consisted of highly ordered sp 2 /sp 3 bonds in its aromatic unit and had less oxygenated functional groups. The photoluminescence measurements showed that MGOH and MGOK QDs emitted yellowish-green and blue light with quantum yields of 15.1% and 8.4%, respectively. The luminescence mechanisms of MOGK and MGOH were attributed to £k-£k? and n-£k? electron transitions in C-C/CC bonds and in £k? states to non-bonding oxygen states, respectively. Density functional theory calculations were employed to determine the optical absorption of GOQDs in terms of surface functional groups and oxygenation degrees. Theoretical calculations demonstrate that the high oxygenation degree of GOQDs resulted in band gap reduction and light absorption due to electron transitions. Our theoretical and experimental results suggested that GOQDs with high quantum yields can serve as promising materials in applications including biosensing, imaging, and labeling. ? 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/410393 | ISSN: | 11440546 | DOI: | 10.1039/c7nj03337k |
顯示於: | 化學工程學系 |
在 IR 系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。